When 4:00 PM - 6:00 PM Oct 30, 2015
Where GM Room, Lurie Engineering Building
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Multiphysics Phase Field Modeling Of Hydrogen Diffusion And δ-Hydride Precipitation In α-Zirconium

Andrea M. Jokisaari
Thesis Defense

Katsuyo Thornton, advisor


The precipitation of hydrides in zirconium is a significant factor limiting the lifetime of nuclear fuel cladding, both during reactor operation and for spent fuel storage. However, the behavior of hydrogen in zirconium has typically been modeled using mean field ap- proaches, which do not account for microstructural evolution. A quantitative, multiphysics phase field model was developed to study the microstructural evolution of δ-hydride precipitates in a single crystal of α-zirconium. The model incorporates CALPHAD-based free energy descriptions of the α-zirconium and δ-hydride phases, solid mechanics, and classical nucleation theory. In particular, nucleation behavior is studied to explain ex- perimentally observed phenomena, such as hysteresis in the terminal solid solubility limit of hydrogen upon hydride dissolution and precipitation, and macroscopic hydride ‘‘reorientation.’’